Vulnerability in HTMLDOC (CVE-2021-43579)

Summary

Vulnerability in HTMLDOC (CVE-2021-43579). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

A stack-based buffer overflow in image_load_bmp() in HTMLDOC <= 1.9.13 results in remote code execution if the victim converts an HTML document linking to a crafted BMP file.

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-43579 has been found in HTMLDOC.
Successful exploitation can lead to full system takeover.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "HTMLDOC CVE-2021-43579" on the vendor's site.

CVE-2021-43579 (HTMLDOC)
Attack vector: local / unauthenticated
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in HTMLDOC.

📍 Affected scope

Check the vendor advisory for the affected versions of HTMLDOC.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'HTMLDOC' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'HTMLDOC' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で HTMLDOC を grep し、稼働しているサービス・バージョンを把握する。
2
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

References

advisory github.com
advisory lists.debian.org
patch github.com
patch github.com
patch github.com